Pumping head and operating mechanism for wells



Sept, 15, 1953 v J. F. JOY 2,651,914

PUMPING HEAD AND OPERATING MECHANISM FOR WELLS Filed Feb. 28, 1950 5 Sheets-Sheet l %:/9 Z0 ma-z \7 k i r Im/enfam Jasep/rfiJoy 1 M FM J. F. JOY

Sept 15 1953 PUMPING HEAD AND OPERATING MECHANISM FOR WELLS Filed Feb 28, 1950 5 Sheets-Sheet 2 i wenior;

J. F. JOY 2,651,914

5 Sheets-Sheet 3 0 ||M| 6 2 mf m z ll 7 l. 6. 0/0 w w Jim .m A L 0 HM U Sept. 15, 1953 PUMPING HEAD AND OPERATING MECHANISM FOR WELLS Filed Feb. 28, 1950 J. F. JOY

Sept. 15, 1953 PUMPING HEAD AND OPERATING MECHANISM FOR WELLS 5 Sheets-Sheet 4 Filed Feb. 28, 1950 F. Afforney Sept. 15, 1953 Y J, oy 2,651,914

PUMPING HEAD AND OPERATING MECHANISM FOR WELLS Filed Feb. 28, 1950 v 5 Sheets-Sheet 5 FROM UYLI NDER FROM PUMP TaAccuMumwR Patented Sept. 15, 1953 PUMPING HEAD AND OPERATING MECHANISM FOR WELLS Joseph F. Joy, Pittsburgh, Pa., assignor to Joy Manufacturing Company, Pittsburgh, Pa., a corporation of Pennsylvania Application February 28, 1950, Serial No. 146,882

10 Claims. 1

This invention relates to a pump, and more especially to a pumping head and operating mechanism of the type used on oil wells.

Modern oil wells often penetrate to very great depths, sometimes as far as ten or fifteen thousand feet. Pumping oil or other liquid from such great depths necessarily takes an enormous amount of power. Inasmuch as the sucker rod drops due to its own weight, power need be applied only to raise it. In order to avoid the large capacity power sources which would be required if the power were applied only half of the time (i. e., to raise the sucker rod), efforts have been made to balance the system. These efforts have not been wholly successful in producing the results desired, and a much improved balanced system is needed.

It is, accordingly, an object of this invention to provide an improved pumping head and operating mechanism for wells in which the pump drive delivers power continuously through a distribution and control means which provides power to lift the sucker rod when necessary and stores power while the rod is being lowered. This and other objects are accomplished in a pump drive having a power distributing and control means consisting of an automatic control valve connected to the power utilizer (the pump head) and to an accumulator. Hydraulic power is supplied constantly to the control valve, which alternately provides power to the pump head cylinder and to the accumulator. When not receiving fluid under pressure from the'hydraulic fluid pump, the cylinder and accumulator are connected to discharge fluid under pressure to the pump, thus serving in effect to supercharge the pump. In the preferred embodiment of the invention, a second accumulator is connected to the pump head cylinder and a safety cutoff valve is positioned in the conduits between the hydraulic fluid pump and the control valve.

In the drawings:

Fig. 1 is a side elevation view of a pump head embodying the invention.

Fig. 2 is a detailed longitudinal section, on a larger scale, through the pump head.

Fig. 3 is a view in section on the same scale as Fig. 2, but showingthe lower end of the connecting rod and the lower end of the pilot valve rod.

Fig. 4 is a longitudinal sectional view on line 4-4 of Fig. 1, showing on an enlarged scale the details of the automatic control valve.

Fig. 5 is a view with parts broken away and in section of the automatic cutoff valve and its connection in the hydraulic system.

Fig. 6 is another sectional view of the cutoff valve, but's'howingit in its operating position in which communication is cut ofi between the hydraulic pump and the control valve, and the pressure fluid from the pump is merely by-passed from the pump discharge to the pump intake through the valve.

Fig. '7 is a side elevation view, with parts broken away and in section, of the cutoff valve shown in Fig. 5, and shows a signal switch attached to the cutoff valve.

Fig. 8 is a schematic diagram of the hydraulic and electric circuits of the invention.

Fig. 9 is a view in section substantially on line 8-9 of Fig. 1, but on a substantially reduced scale.

Fig. 10 is a diagrammatic view of the control valve showing it in position to direct hydraulic fluid under pressure from the hydraulic pump to the pump head, and to conduct hydraulic fluid from the accumulator to the hydraulic pump.

Fig. 11 is a diagrammatic view showing the control valve in a position in which the pilot valve has been moved from the position shown in Fig. 10 to a position in which hydraulic fluid under pressure is admitted to the upper end of the valve for the purpose of moving the control valve to the position shown in Fig. 12.

Fig. 12 is a diagrammatic view of the control valve showing the valve in position to direct fluid from the hydraulic pump to the accumulator and to receive fluid from the pump head to the hydraulic pump; and

Fig. 13 is a diagrammatic view showing the pilot valve moved from its position of Fig. 12 into position to admit fluid under pressure to the lower end of the valve in order to move the valve to the operating position shown in Fig. 10.

Figs. 1 and 2 show an oil well pump head having a hydraulic lift cylinder 2 in which a piston 4 is mounted for reciprocation. Piston f is secured to a piston rod 6. Piston rod ii is connected at its lower end by any suitable means as by a polished rod grip 8 and polished rod 9 to the sucker rod Ill and carries a pilot valve actuator l2.

Lift cylinder 2 of the oil well pump head is preferably a single acting hydraulic cylinder having a fluid connection I4 at its lower end to supply hydraulic fluid under pressure, and having restricted communication with the atmosphere at its upper end by means of one or more ports [6. A protective cap [8 is preferably provided to keep dirt out of the ports I6. An accumulator 26 of the enclosed bladder type, such as is shown in U. S. Patent No. 2,256,835 to Mercier, is preferably mounted to communicate with the lower end of cylinder 2 by way of a oneway restriction connection 2i in order to provide capacity to receive the discharge of hydraulic fluid from the cylinder 2 and the hydraulic pump after the control valve reverses near the end of the downward stroke of piston 4, The considerable kinetic energy of the pumping mechanism, in motion during the downward stroke, must be absorbed by some means. Such means are provided by the accumulator 20.

The connection I4 preferably consists'of a conduit connected at its one end to the lower end of the aforesaid cylinder 2, and atits other end to an automatic control valve 22. Connection I4 is preferably provided with a charge connection 23 (Fig. 8), to permit a fluid charging unit to be connected for the purpose of charging the system with hydraulic fiuid in the desired amount and to the desired pressure. A purge tank 24 is preferably provided in the conduit I4 in order to allow the purging or escape of entrained air by way of a manually operable valve 26.

The automatic control valve 22 is provided with a pilot valve which will be described in greater detail below. The pilot valve is reciprocated by means of actuating rods 2'! at its upper end and 28 at its lower end- Rods 21 and 28 carry collars 29 and 32 respectively, to be engaged by pivotally mounted arms 3i and 32 respectively. The arms 3! and 32 are pivotally mounted to project through slots in a substantially cylindrical casing 33. In the preferred form of the invention, the casing 33 is provided with a plurality of slots 34 and 35. A bracket 36 is preferably mounted adjacent the slots '34, and a bracket 31 adjacent the slots 35. The brackets have openings 38 to receive the hinge pins 59 of the pivoted arms 3| and 32. As will'be understood by those skilled in the art, the slots 34 and admit of a certain amount of choice in the location of arms 3| and 32 to permit variation in the length of operating stroke of the pump which is actuated by rod 6.

As is best seen in Figs. 2 and 3, arm 3I carries an extension 459, with a rol1er'42 at the end of the extension and another roller 44 at the angle formed by the extension with its arm. Similarly, arm 32 carries an extension 45, with a roller 48 at the end of the extension and another roller 50 at the angle formed by the extension 46 with its arm 32. 32, their extensions, and the rollers, are so proportioned as to permit a considerable amount of overtravel by the piston 4 and actuator I2 after reversal of the pilot valve. Moreover, the angle formed by the extensions with their respective arms is such as to hold the end rollers 42 and 48 in the path of the actuator I2 when the latter moves toward a roller to reverse the position of the pilot valve.

As is best seen in Fig. 3, polished rods 8 are connected by means of a boss 5! to the lower end of actuator I2. The boss 5| and arm 32 with its associated extension and rollers are so proportioned that arm 32 is not engaged by the boss 5|,

but holds its extreme counterclockwise position until tripped by the actuator I 2.

In order to hold actuator I2 against excessive lateral movement, guides 52 (one of which is shown in Fig. 3) may be provided at opposite The actuator I2, the arms 3|,

sides of actuator I2 to engage in slots or, preferably, enclosed guideways 53 in the casing 33.

A second accumulator 54, of the enclosed bladder type referred to above, is connected to the control valve 22 by means of a conduit 56. Hydraulic fluid under pressure is supplied to the control valve 22 by means which include a conduit 58 and a conduit 60, and fluid is returned from the valve to the hydraulic fluid pump by means which include a conduit 62 and a conduit 64. The fluid pump referred to is shown at 66 in Figs. 5 and 8, and, in order to permit variation of the output of the well, is preferably a manually controllable, variable displacement pump. Pump 66 is provided with discharge and intake connections 65a and 661) respectively.

The means to conduct fiuid under pressure from the fluid pump 66 to the control valve 22, and the means to conduct fluid from the valve 22, to the pump 66, also includes the body 88 of a cutoff valve indicated generally at It. The housing or body 158 is provided with a central bore having a relatively large diameter .at its lower .end, hereinafter referred to as bore 12, and a smaller diameter at its upper end, hereinafter referred to as bore I4. As is readily seen in Fig. 5, portions of both bores are included in the means to conduct fluid under pressure from the fluid pump 66 to the control valve 22, and a portion of bore I2 is included in the means to conduct fluid from the valve 22 to the pump 66. To that end, conduit 58 communicates with the central bore of the valve body by means of a threaded bore I6 intersecting the bore 14 of the valve body; conduit 60 communicates with the central bore by means of a threaded bore 18 which intersects bore I2; conduit 62 communicates with the central bore by means of a threaded bore which intersects bore I2; and conduit 64 communicates with the central bore by means of a threaded bore 82, which also intersects bore I2.

Reference will now be had to Fig. t for a detailed consideration of the automatic control valve 22. A valve body or housing 26 is provided with a central bore in which is fitted a sleeve 88. The housing 86 is provided with annular grooves 90, 92, 94, S6, and 28. Sleeve 88 is provided with five sets of ports H32, H32, I24, I536, and I08 aligned with annular grooves 26, 92, 94, 96, and 98 respectively.

A valve member indicated generally at H2 is provided with end pistons I I2 and I I4, and with lands or plugs H6 and I I8 between the pistons H2 and H4. The smaller diameter of the valve member H9 between the pistons and the lands forms, with the pistons and the lands, a plurality of grooves I20, I22 and I24. As will be understood by those skilled in the art, the pistons I I2 and H4 and the lands H6 and H8 preferably provide a smooth sliding fit.

The valve member H0 is provided with a central bore I26 between the pistons H2 and H4. The pistons are hollow, providing larger bores than. the bore !26 in communication with that bore. A set of ports I28 is arranged in the valve member between piston H2 and land H6; a second set of ports I30 is provided in the valve member III! between the lands H6 and H8; and a third set of ports I32 is provided between the land IE8 and the piston H4. The lands H6 and H8 are so spaced as to completely plug or cover the ports I02 and W6 respectively, with the valve member IID located midway between its two extremes of movement, as seen in Fig. 4.

A pilot valve indicated generally at I34 is carlied on the actuating rods 21 and 28 and is mounted for movement in the .bore I26. Pilot valve I34 is provided with a central bore which is blocked off or plugged by a plug I36 substantially midway between its ends, thus dividing the central bore into two parts I 31 and I38. The pilot valve carries end lands I40 and I42 which fit in the central bore I26 of the valve member I I 9. As can be seen in Fig. 4, land I40 is disposed in that end of bore I26 which is associated with piston IIZ, and land I42 disposed in that end of bore I26 which is associated with piston II4. Actuating rod 21 is secured to the pilot valve by means of a head I44, which is provided with radial ports I46 to communicate the bore half I51 with the hollow of piston H2 and thereby the interior of sleeve 88. Actuating rod 28 is connected to the pilot valve by means of a head I48 which is provided with radial ports I50 to communicate the bore half I38 with the hollow of piston H4 and thereby the interior of sleeve 88.

Pilot valve I34 is provided midway between its ends with a land I52. A land I54 is provided between the lands I40 and I52. A land I56 is provided between the lands I42 and I52. The lands I40, I42, I52, I54 and I56 are of such a diameter as to provide a smooth sliding fit of the pilot valve I34 in the bore I26. Under some circumstances, it may be found desirable to make one or more of the lands small enough to provide a little clearance between the outer periphery of the land and the bore I28, as is shown in Fig. of my copending application Ser. No. 73,625, filed January 29, 1949.

Pilot valve I 34 is of a smaller diameter between the lands to provide a groove I58 between lands I40 and I54; a groove I68 between the lands I54 and I52; a groove I62 between the lands I52 and I56; and a groove I64 between the lands I56 and I42. A set of ports I66 communicates the bore I31 with the groove I60, and another set of ports I68 communicates the bore I38 with the groove I62.

The valve is provided with suitable end caps I10 which will not be described in detail herein, inasmuch as the details thereof form no part of this invention and are, furthermore, set forth in my above-identified patent application.

Reference is now made to Figs. 5, 6 and '1 for a detailed consideration of the cutoff valve 10. It was pointed out above that conduits 58 and 68 communicate through the bore 14 and the upper end of bore I2, and that conduits 62 and 64 communicate through the lower end of bore 12. A spool-type valve member I12 is mounted for reciprocation in the two bores 12 and 14. Valve member I12 consists of a large diameter piston I14 reciprocable in the bore 12 and a smaller piston I16 reciprocable in the smaller bore 14. In its operating position in which fluid is allowed to pass from pump 66 to the valve 22 by way of valve I8, piston I14 occupies a position in the bore 12 between the two connections 18 and 82, as is seen in Fig. 5. With the valve in this operating position, piston I16 is at the upper end of bore 14. Piston I16 is provided with bleed passages I11 to prevent the pocketing of fluid in the hollow of valve member I12 and below piston I14 when member I12 is moved downward into cutofi position.

At its upper end, valve member I12 is provided with an extension in the form of a rod I18. Rod I18 carries near its upper end a pair of cars I80 and I02. Outward and upward extending arms I84 and I86 are mounted on the upper end of the valve body 68, preferably integral therewith. Arms I84 and I86 carry mounting ears I88 and I90 which cooperate with the ears I and I82 respectively, to mount a pair of springs I92 and I94 respectively.

The two mounting units are identical, so it will suffice to describe one of them in detail. The ear I82 pivotally carries a plunger I96, which cooperates with a socket I98, which is in turn pivotally carried on the ear I98. The spring I94 is compressed between spring pads 200 and 202 on the plunger and socket respectively. Thus, the rod I18, arms I84 and I86, springs I92 and I94, and their associated mounting means form a toggle mechanism having a spring bias which opposes the downward movement of the valve member I12.

It will be noted that the pistons I14 and I16 differ in diameter by only a very small amount, with the result that the annular areas of these pistons which are exposed to the pressure in bore 14 are not greatly different. This small difference in areas makes it possible to use relatively light or soft springs I92 and I94 to oppose downward movement of valve member I12 from the operating position shown in Fig. 5 to the operating position shown in Fig. 6.

Referring now to Fig. 7, it will be seen that rod I18 also carries at its upper end, on the link to which ears I80 and I82 are attached, a substantially horizontally extending arm 284. The outer end of arm 294 carries an adjustable, downward extending abutment 205 in the form of a set screw. Valve body 68 carries a switch 208 having an actuating plunger 2I8 positioned and aligned to be engaged by the abutment 205. The switch 288 is disposed in the circuit of any suitable signal device, such as a light or a bell 2I2, by means of electrical conduit 2I4. The circuit includes any suitable power source 2I5.

As will be understood by those skilled in the art, the signal means may if desired comprise mechanism for shutting down the fluid pump drive. To that end, the switch 288 could be used to operate a relay to interrupt the power supply to the hydraulic pump drive motor, such as shown at 2I8, where the latter is electrically driven. Inasmuch as many oil field operations are performed with small internal combustion engines, the switch 288 could be disposed in the ignition circuit of such engine, to the end that opening of switch 208 would open the ignition circuit and stop the engine. In that case, of course, switch 208 would be a normally-closed switch instead of the normally-open switch shown in Fig. 8.

Reference is now made especially to Figs. 1 and 9, showing the improved base of the oil well pump head. As can be seen in these two figures, the pump head is supported on an open ring 228 and legs 222, the assembly forming a tripod type of support for the pump head. The ring is secured in place by being fastened as by means of bolts 223, 224, and 225 to a base plate 226 mounted on any suitable ground support members 221. A fourth ground support member 228 is provided for engagement by the ring 220 when it is swung out of pumping position into the dotted line position shown in Fig. 9 to provide better access to the well. To enable the easy swinging of the pump head about the bolt 223 as a pivot, a handle 230 is provided. Handle 230 is removably engageable in a socket 232 suitably 7 secured to the ring 220. The ground support member 2-28 is provided with an opening 234 to receive the bolt 2 24 to hold the ring 220 in the position shown in dotted lines in Fig. 9.

Operation Before describing the operation of the pumping head as such, the steps required to prepare the system for such operation will be set forth here. To prepare the system for operation, it is referable to start by weighing the well. By reason of the weight of the sucker rods, those rods will normally be at the bottom of their stroke; what is meant by weighing the well-is determining the approximate weight of the .rods,

or the force required to balance the reciprocating parts of the entirepump.

This is accomplished by filling the system with oil (or other suitable liquid) under pressure until the sucker rods and other reciprocating parts are caused to move upward. As will be understood by those skilled in the art, the charging apparatus will be connected to the connection 23 (Figs. 1 and i3), and the charging apparatus will normally be provided with a gage to indicate pressure. The gage pressure in pounds per square inch on the oil, when upward movement takes place, should be noted as Weight of well; that is the pressure required to balance the moving parts. When this pressure is known, the air end of the accumulators 26 and 54 should be charged with air or other gas to pressure slightly in excess of the pressure indicated by the gage indicating the weight of the well. Oil is then added in such amount as will move the rods upward to approximately the center of the working stroke, whereupon the working or moving parts may be considered as being in balance and ready for trial operation.

By trial operation is meant that period during which entrapped air is purged from the oil in the system by way of purge tank 24 and valve 26, and make-up oil is introduced; during this stage, gas is added to or bled from the accumulators to obtain the proper balance of the working parts and to achieve smoother operation. When the system is properly balanced, a pressure gage in the discharge line of the hydraulic fluid pump should indicate approximately the same pressure on the down-stroke as it shows on the upstroke of the sucker rod.

Reference is now made to Fig. 8, in particular, for a detailed discussion of the normal operation of a head made according to this invention. The normal operating position of cutoff valve '58 is that shown in Fig. 5, in which position the hydraulic fluid pump 56 delivers fluid under pressure to the automatic control valve 22 by means consisting of conduit 60, a part of the central bore of valve it including portions of bores '52 and T4, and conduit 58. Let it be assumed that valve 22 is in the operating position shown in Fig. 10. Valve 22 always receives fluid under pressure by way of conduit 58. With valve 22 in the position shown in Fig. 10, and as shown in the dotted line in that figure, fluid flows under pressure from conduit 58 into the annular groove 94, through ports I84, into groove I22, through ports 152, into groove 92, to the pump head cylinder 2 by way of conduit I4. Fluid under pressure is thereby admitted to the under side or face of piston 4, and raises it to lift piston rod 6 and the connected sucker rod I0.

Meanwhile, accumulator 54, which has been charged with fluid under pressure during the previous downward stroke of piston 4, discharges its fluid under pressure by way of conduit 56 into annular groove 96 of valve 22, through ports I00 into .groove I24, out through ports I03, into groove 98 as shown by the dot-dash line in Fig. 10, and back to the fluid pump 66 by way of conduit 62, a part of the central bore of valve 10 including a portion of bore I2, and conduit 64. Thus, the fluid under pressure from accumulator 54 superoharges fluid pump 66 by providing hydraulic fluid under pressure to the pump intake.

A piston 4 nears'the upper limit of its movement, the actuator 'l 2 (Fig. 3) engages the pivoted arm 3i (Fig. 2) and moves it counter-clockwise about its pivot 39. This counter-clockwise movement causes arm 3| to engage collar 29 on actuator'rod 2'! and moves the rod downward, moving the pilot valve I34 from the position it occupies in Fig. 10 to the position shown in Fig, 11. In the latter position, fluid under pressure is delivered from pump 66 to conduit 58, into groove 94, through ports I514 into groove I22, through ports I30 into groove I60, through ports I66 into bore I31, out through radial ports I46 and into the space above head I44, as shown in dotted lines in Fig. 11. The head I44 and piston I I2 are thus subjected at their upper faces to pump discharge pressure, and the valve parts thereupon move to the position shown in Fig. 12.

With the parts of valve 22 in the operating position shown in Fig. 12, fluid under pressure is admitted from conduit 58 into the annular groove 94, through the ports I04, into the groove I22, out through ports I06, into annular groove 96 and out through conduit 56 to the accumulator 54. Thus, during the return or downward stroke of piston 4, accumulator 54 is connected with fluid pump 66 and is charged with hydraulic fluid under pressure.

Meanwhile, because of the downward movement of piston 4, occasioned by the tremendous weight of the sucker rods, piston 4 moves downward and forces hydraulic fluid out of cylinder 2 by way of conduit I4 to valve 22, where the fluid enters groove 92, passes through ports I02 into groove I20, out through ports I00, and to the pump intake by way of conduits 62 and 64, and a portion of bore 72 of valve I0. Thus the pump is also supercharged during this phase of the cycle of operation.

As the piston 4 nears the lower end of its stroke, the actuator I2 engages the arm 32 (Fig. 3) and 'moves it clockwise about its pivot 39. This movement causes the outer end of arm 32 to engage collar 36 and moves actuator rod 28 upward, moving the pilot valve from the position it occupies in Fig. 12 to the position shown in'Fig. 13. In the latter operating position, fluid is admitted under pressure from conduit 58 into groove'04, whence it passes through ports I04 into groove I22, into ports I30, into groove I62, through ports I68, through the bore I38, and outward through the radial ports I50. Here fluid is admitted under pressure to the entire lower end of piston I I 4 and head I48, moving the valve into the operating position shown in Fig. 10, whereupon the cycle begins all over.

By reference to my above-identified patent application, it will be well understood by those skilled in the art that fluid pressure will normally move the valve member I I0 and the pilot valve I34 from the position shown in Fig. 11 to the position shown in Fig. 12. However, if the main valve member I I0 should stick for some reason or other, the mechanical actuation of the pilot valve I34 will loosen the main valve member H0, be-

cause of the abutment of the inner face of the head against the end of the inside of the piston in which the head is located.

It will further be understood by reference to the above-identified patent application that the pilot valve will normally reach the end of its movement first, and that the clearance provided between the outer periphery of the end land on the pilot valve and the bore I26 of the main valve will provide a metering effect of the fluid which is being expelled from that end of the valve to which the main valve member and the pilot valve are moving. This metering effect will serve to cushion the stop of the main valve member I I0.

Reference will now be made in detail to the operation of the cut-off valve ill. Let it be assumed to begin with that the sucker rod breaks as the piston 4 moves downward. If failure occurs during this part of the cycle, it is evident that the pressure in the bore 12 below piston I14 will drop to substantially nothing, because during this part of the cycle the cylinder 2 is discharging fluid to the pump intake. When a sucker rod breaks, the weight on the piston rod 6 Will be substantially reduced, thus diminishing the pressure under which cylinder 2 discharges its fluid through the valve 22, through conduit 62, bore '12 and conduit 64. The pressure, nevertheless, in bore M above piston il will still be very high, because the pump is discharging through bore 1'4 into the accumulator 54. There will thus be a substantial pressure differential exerting a downward force on the piston I14 sufficient to overcome the bias of Springs I92 and I94, moving the spring-toggle-operated mechanism past its dead center, and into the position shown in Fig. 6.

With the parts as shown in Fig. 6, piston H4 completely cuts off communication between conduits 62 and 64, and piston H6 completely cuts oil communication between conduits B and 60. However, with the parts in this position, flow is readily permitted between conduits 60 and 64. Thus, the automatic control valve is by-passed by the new operating position of the cutoff valve H1.

When the toggle mechanism moves into the position shown in Fig. 6, the abutment 2H6 engages the plunger 210, and closes the circuit for the signaling device 212. The signaling device is located where the signal will be brought to the attention of the operator who will be apprised of the fact that something is wrong and will then shut down the machine and take steps to correct the difiiculty.

Alternatively, a normally-closed switch instead of the normally-open switch shown at 293, interposed in the ignition circuit of an internal combustion engine or in the relay circuit of an electric drive motor, would shut down the drive means and thus stop the fluid pump. Other variations on the control means will occur to those skilled in the art.

Let it now be assumed that the sucker rod breaks on the upstroke of piston 4. During this phase of the cycle, cylinder 2 is connected to receive fluid under pressure. Therefore, when the break occurs in this phase of the cycle, the pressure in the conduits 58 and 60 and, therefore, the pressure above piston I14, will fall to substantially zero. The pressure below piston H4 will continue high, because during this phase of the cycle the accumulator 54 is discharging oil under pressure to the pump intake. Valve member I12 will, therefore, remain in the position shown in Fig. 5 until piston 4 has moved to its upper limit of movement, whereupon actuator l2 will reverse the pilot valve i234. With the valve reversed, the accumulator is again connected to receive fluid under pressure from the pump, whereupon the conduits 58 and 6t, and the upper face of piston I74 are subjected to pressure. The valve is then operating under the same circumstances as when the sucker rod breaks on the downward stroke. That operation was described above and need not be repeated here.

It may be noted that, if a sucker rod should break on the up-stroke, piston 4 nevertheless does not move upward fast enough to damage the upper end of cylinder 2, for the reason that oil cannot be supplied fast enough to cylinder 2. The capacity of pump 66 is such that, even in the absence of a back pressure on the discharge, it will not discharge oil in sufiicient volume to move piston i at an injurious speed. Moreover, accumulator 20 discharges oil through the connection 2|, which is designed to limit the discharge of oil to a safe rate. Accordingly, although the rate of discharge of oil from pump 66 and accumulator 20 into cylinder 2 will under these circumstances be greater than under normal operating conditions, it will still not be so great as to move piston 4 upward fast enough to damage the pump cylinder. It will of course be understood by those skilled in the art that the connection 2| restricts oil flow in only one direction, and that oil may be forced into accumulator 28 without hindrance on the part of connection 2|.

Reference will now be had to Fig. 9 for an understanding of the operation of the swingable base of my improved pumping head. With the pump head disconnected, bolts 224 and 225 are removed. Handle 230 is inserted in socket 232, and the pump head is swung about bolt 223 into the dotted line position shown in Fig. 9. Bolt 224 is then screwed into threaded opening 234! to hold the pumping head in place. After work on the well has been completed, the pumping head is restored to its normal operating position.

It will be evident to those skilled in the art that the oil well pumping head set forth herein provides a nicely balanced system in which the fluid pump works full time instead of a hydraulic pump twice as large working half of the time. Furthermore, an improved pumping head made according to this invention is readily swung out of the way to permit work on the well to take place, and is as readily swung back into place following the completion of such work. Other advantages will be apparent to those skilled in the art.

While there is in this application specifically described one form which the invention may assume in practice, it will be understood that this form of the same is shown for purposes of illustration, and that the invention may be modified and embodied in various other forms Without departing from its spirit or the scope of the appended claims.

I claim:

1. In a balanced system of deep-well pumping, a pump head cylinder having a working stroke and a return stroke, a hydraulic fluid pump having discharge and intake connections, an accumulator, and means including a valve to connect the discharge connection with the pump head cylinder during the working stroke and 11 with the accumulator during the return stroke and to connect the intake connection with the accumulator during the working stroke and with the pump head cylinder during the return stroke, and including also a cutofl valve adapted, upon the occurrence of a condition relieving said cylinder of its working stroke load, to interrupt fluid flow to the pump head cylinder and to connect the pump discharge with the pump intake.

2. In a balanced pump head, in combination, a pump head cylinder, a piston reciprocable in the cylinder, a hydraulic fiuid pump having a discharge connection and an intake connection, a control valve, an accumulator, means to conduct fluid under pressure from the pump to the valve, .means to conduct fluid under pressure from the valve to the pump, said two conducting means including a cutoff valve adapted, upon the occurrence of a predetermined change in the pressure difference between pump discharge and pump intake, to interrupt fluid flow to the control valve and to connect the pump discharge with the pump intake, conduit means connecting the control valve with the cylinder, and conduit means connecting the control valve with the accumulator.

3. A balanced pumping head comprising, in combination, a pump head cylinder, a piston reciprocable in the cylinder, a hydraulic fluid pump having discharge and intake connections, a control valve, an accumulator, conduit means to conduct fluid under pressure from the fluid pump to the valve, conduit means to conduct fluid under pressure from the valve to said pump, a valve body having a central bore, connections communicating said bore with the first-named conduit means such that said conduit means includes at least a portion of the bore, connections communicating said bore with the second-named conduit means such that said conduit means includes at least a portion of the bore, a valve member reciprocable in the bore, the valve member having one operating position in which fluid flow is permitted from the pump to thecontrol valve and from the control valve'to the pump and another operating position connecting the pump discharge and intake connections and in which flow between the pump and the control valve'is out 01f, conduit means connecting the control valve with the cylinder, and conduit means connecting the control valve with the accumulator.

4. A combination according'to claim 3, in which the valve member is biased toward one operating position by pressure in the conduit means from the pump to the control valve and toward its other operating position bypressure in the conduit means from the control valve to the pump, and means to prevent valve member movement from its first-named operating position to its second until the existence of a predetermined difierential between the pressure in the conduit means from the pump to. the. control valve and the pressure in the conduit means from the control valve to the pump.

5. A combination according to. claim 3, in which the valve member is biased toward its outoff position by pressure in the conduit means from the pump to the control valve and toward its other operating position by pressure in the conduit means from the control valve to the pump, and means to prevent valve member movement from its first-named operating position to its second until the pressure in the conduit means from the pump to the control valve is greater by a predetermined amount than the pressure in the conduit means from the control valve to the pump.

6. A combination according to claim 3, in which the valve member is biased toward one operating position by pressure in the conduit means from the pump to the control valve and toward its other operating position by pressure in the conduit means from the control valve to the pump, and spring-toggle-operated means to prevent valve member movement from its firstnamed operating position to its second until the pressure in the conduit means from the pump to the control valve is greater by a predetermined amount than the pressure in the conduit means from the control valve to the pump.

7. A balanced pumping head comprising, in combination, a hydraulic cylinder, a piston reciprocable in the cylinder, a hydraulic fluid pump, a control valve, an accumulator, means to conduct fluid under pressure from the pump to the valve, means to conduct fiuid under pressure from the valve to the pump, the last twomeans including a cutoff valve mechanism adapted to interrupt fluid flow upon the occurrence of a predetermined change in load on the piston, conduit means connecting the control valvewith the cylinder, conduit means connecting the control valve with the accumulator, and signal means connected to be actuated to give a signal upon movement of said cutoff valve to its cutoff position.

8. A combination according to claim 7', in which the signal means is electrically operated.

9. A combination according to claim 8, in. which the signal means comprises an abutment mounted for movement upon movement of the cutoff valve into fluid-interrupting position, and a switch positioned to be engaged by said abutment and connected in the circuit of the signal means.

10. A combination according to claim 7-, and means to drive said fluid pump; said signal means comprising means to stop the operation of said drive means.

JOSEPH F. JOY.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 920,825 Clark May 4, 1909 1,506,583 Hoffman Aug. 26, 1924 1,879,262 Hubbard Sept. 27, 1932 2,027,104 Kahr et al. Jan. 7, 1936 2,141,703 Bays Dec. 27,1938 2,167,623 Britter Aug. 1, 1939 2,245,960 Claire June 17, 1941 2,247,238 Johnston June 24, 1941 2,277,761 Hubbard Mar. 31, 1942 2,279,057 Reed Apr. 7, 1942 2,347,301 Twyman et al. Apr. 25, 1944 2,555,427 Trautman June 5, 1951 2,562,837 White July 31, 1951 

